Integrated VCO having an improved tuning range over process and temperature variations
AssigneeBroadcom Corporation
InventorsRalph Duncan, Tom W. Kwan
Life of this patent
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Abstract
An integrated VCO having an improved tuning range over process and temperature variations. There is therefore provided in a present embodiment of the invention an integrated VCO. The VCO comprises, a substrate, a VCO tuning control circuit responsive to a VCO state variable that is disposed upon the substrate, and a VCO disposed upon the substrate, having a tuning control voltage input falling within a VCO tuning range for adjusting a VCO frequency output, and having its tuning range adjusted by the tuning control circuit in response to the VCO state variable.
Claims7
An integrated VCO circuit comprising:
- a VCO having a pair of driver transistors and a tank circuit;
- and
- a tuning control circuit producing a sliding voltage window coupled to said tank circuit for adjusting the frequency range of the VCO, said sliding voltage window having a fixed voltage magnitude with a sliding center voltage that is responsive to temperature so as to compensate for temperature change in said pair of driver transistors.
An integrated VCO circuit comprising:
- a VCO having a pair of driver transistors and a tank circuit;
- an adaptive bias circuit coupled to said driver transistors that maintains a nearly constant transconductance in said pair of driver transistors in response to changing circuit temperature;
- and
- a tuning control circuit coupled to said tank circuit that has a window of control voltages, said window having fixed voltage magnitude with a sliding center voltage that is responsive to temperature;
- wherein maintaining a constant transconductance in said driver transistors assists in maintaining said sliding center voltage of said window of control voltages.
A method for minimizing non-linear effects of temperature variation in an integrated VCO having a tuning control circuit with a sliding voltage window, and a pair of driver transistors, the method comprising:
- sensing ambient circuit temperature;
- varying a gate-to-source voltage of each of the pair of driver transistors in response to the ambient circuit temperature to maintain nearly constant transconductance in the pair of driver transistors;
- and
- adjusting the sliding voltage window in response to said varying gate-to-source voltage of each of the pair of driver transistors.
An integrated VCO circuit comprising:
- a pair of driver transistors;
- a tank circuit coupled to said pair of driver transistors;
- a tuning control circuit having a sliding voltage control window coupled to said tank circuit for setting a frequency tuning range;
- a means for maintaining a constant transconductance in said driver transistors over varying temperature conditions;
- and
- a means for adjusting a center voltage for said sliding voltage control window over varying temperature conditions.
Dependencies are inferred from the claim text.